Question: When I was reading Saturn, I wondered where is the Cassini spacecraft

Answer:

Cassini–Huygens is a joint NASA robotic spacecraft mission currently studying the planet Saturn and its many natural satellites. The spacecraft consists of two main elements: the NASA-designed and -constructed Cassini orbiter, named for the Italian-French astronomer Giovanni Domenico Cassini, and the ESA-developed Huygens probe, named for the Dutch astronomer, mathematician and physicist Christiaan Huygens. The complete Cassini space probe was launched on October 15, 1997, and after a long interplanetary voyage, it entered into orbit around Saturn on July 1, 2004. On December 25, 2004, the Huygens probe was separated from the orbiter at approximately 02:00 UTC. Then, it reached Saturn's moon Titan on January 14, 2005, when it made a descent into Titan's atmosphere, and downwards to the surface, radioing scientific information back to the Earth by telemetry. On April 18, 2008, NASA announced a two-year extension of the funding for ground operations of this mission, at which point it was renamed to Cassini Equinox Mission. This was again extended in February 2010 and the mission may potentially continue until 2017. Cassini is the first space probe to orbit the planet Saturn and the fourth one to visit Saturn.
This weekend, Cassini were getting the lowdown on Titan. NASA's Cassini spacecraft will take its lowest dip through the hazy atmosphere of Saturn's moon Titan in the early morning of June 21 UTC, or June 20 Pacific Time.

Cassini entered orbit around Saturn on July 1, 2004. On 25 December 2004 the Huygens probe separated from the ship at approximately 02:00 UTC. The probe reached Saturn's largest moon, Titan on January 14, 2005, when that came down to the surface to collect scientific information.This is the first spacecraft to orbit Saturn and the fourth human space artifact visit.

Cassini Saturn Orbit Insertion.jpg
Cassini Saturn Orbit Insertion.jpg
Artist's concept of Cassini's Titan flyby
Artist's concept of Cassini's Titan flyby